dm: scsi: Rename CONFIG_CMD_SCSI to CONFIG_SCSI

This option currently enables both the command and the SCSI functionality.
Rename the existing option to CONFIG_SCSI since most of the code relates
to the feature.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/README b/README
index 88ff837..33dc788 100644
--- a/README
+++ b/README
@@ -1066,7 +1066,7 @@
 		CONFIG_CMD_RUN		  run command in env variable
 		CONFIG_CMD_SANDBOX	* sb command to access sandbox features
 		CONFIG_CMD_SAVES	* save S record dump
-		CONFIG_CMD_SCSI		* SCSI Support
+		CONFIG_SCSI		* SCSI Support
 		CONFIG_CMD_SDRAM	* print SDRAM configuration information
 					  (requires CONFIG_CMD_I2C)
 		CONFIG_CMD_SETGETDCR	  Support for DCR Register access
@@ -1254,7 +1254,7 @@
 		CONFIG_MTD_PARTITIONS  Memory Technology Device partition table.
 
 		If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
-		CONFIG_CMD_SCSI) you must configure support for at
+		CONFIG_SCSI) you must configure support for at
 		least one non-MTD partition type as well.
 
 - IDE Reset method: